a two-phase model for smoothly joining disparate growth phases in the macropodid thylogale billardierii两阶段模型顺利加入不同的增长阶段macropodid thylogale billardierii.pdfVIP

A Two-Phase Model for Smoothly Joining Disparate Growth Phases in the Macropodid Thylogale billardierii 1 1 2 1 3 Clive R. McMahon , Marie-Jeanne Buscot , Natasha L. Wiggins *, Neil Collier , John H. Maindonald , Hamish I. McCallum4, David M. J. S. Bowman2 1 Research Institute of Environment and Livelihoods, Charles Darwin University, Darwin, Australia, 2 School of Plant Science, University of Tasmania, Hobart, Australia, 3 Centre for Mathematics and its Applications, Australian National University, Canberra, Australia, 4 Griffith School of Environment, Environmental Futures Centre, Nathan campus, Nathan, Griffith University, Queensland, Australia Abstract Generally, sigmoid curves are used to describe the growth of animals over their lifetime. However, because growth rates often differ over an animal’s lifetime a single curve may not accurately capture the growth. Broken-stick models constrained to pass through a common point have been proposed to describe the different growth phases, but these are often unsatisfactory because essentially there are still two functions that describe the lifetime growth. To provide a single, converged model to age animals with disparate growth phases we developed a smoothly joining two-phase nonlinear function (SJ2P), tailored to provide a more accurate description of lifetime growth of the macropod, the Tasmanian pademelon Thylogale billardierii. The model consists of the Verhulst logistic function, which describes pouch-phase growth – joining smoothly to the Brody function, which describes post-pouch growth. Results from the model demonstrate that male pademelons grew faster and bigger than females. Our approach provid